feat: full artist release list via artist/getReleasesList

Instead of relying on the limited preview in artist/page, fire a
separate artist/getReleasesList request per release type (album,
epSingle, live, compilation) in parallel when loading an artist.
Each result updates its section independently as it arrives, so the
page populates progressively without a single large request.

Also fixes the artist name in the status bar (was reading wrong field).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/backend/qobuzbackend.hpp

@@ -4,6 +4,7 @@
 
 #include <QObject>
 #include <QString>
+#include <QJsonArray>
 #include <QJsonObject>
 #include <QTimer>
 
@@ -29,6 +30,7 @@ public:
     void search(const QString &query, quint32 offset = 0, quint32 limit = 20);
     void getAlbum(const QString &albumId);
     void getArtist(qint64 artistId);
+    void getArtistReleases(qint64 artistId, const QString &releaseType, quint32 limit = 500, quint32 offset = 0);
     void getPlaylist(qint64 playlistId, quint32 offset = 0, quint32 limit = 500);
 
     // --- favorites ---
@@ -83,6 +85,7 @@ signals:
     void searchResult(const QJsonObject &result);
     void albumLoaded(const QJsonObject &album);
     void artistLoaded(const QJsonObject &artist);
+    void artistReleasesLoaded(const QString &releaseType, const QJsonArray &items);
     void playlistLoaded(const QJsonObject &playlist);
     void playlistCreated(const QJsonObject &playlist);
     void playlistDeleted(const QJsonObject &result);